July 16 (HealthDay News) -- Individuals who are poor candidates for organ transplantation may improve their odds with a new combination therapy.

According to the authors of a study in the July 17 issue of the New England Journal of Medicine, roughly one-third of the 74,000 patients waiting for a transplant from a deceased donor are "sensitized."

This means they have previously been exposed to human leukocyte antigens (HLA). According to the National Marrow Donor Program, HLA refers to protein markers on most of the cells in the human body. These markers help the immune system identify which cells are supposed to be there and which are not.

Patients who are sensitized to human leukocyte antigens (HLA) often aren't able to get organ transplants because their immune systems respond so voraciously to the HLA targets, effectively rejecting the new organ.

According to the study, only 6.5 percent of "highly sensitized" patients are able to undergo a transplant each year. Without a transplant, these individuals have to be hooked up to cumbersome dialysis machines to stay alive.

The senior author of this study, Dr. Stanley C. Jordan, medical director of the Renal Transplant Program at Cedars-Sinai Medical Center in Los Angeles, had previously developed high-dose intravenous immunoglobulin (IVIG) therapy to desensitize these patients.

For this early-phase trial, Jordan and his colleagues looked at combined IVIG and Rituxan (rituximab), a monoclonal antibody, in sensitized patients.

The combination had better success rates than IVIG alone: Eighty percent of patients receiving both drugs were able to get a transplant. All patients survived to the end of one year.

The combined therapy is also less costly than IVIG alone.

"Patients who are on dialysis and those who are progressing toward renal failure should be considered for a kidney transplant. Ideally, they would be referred to a transplant center for evaluation even before they start dialysis, because data show that those who get transplanted before starting dialysis do better," Jordan said in a hospital news release. "However, for the highly sensitized patient, transplantation is not an option unless desensitization therapies are used."

The findings need to be validated in further trials, said both study authors and the authors of an accompanying editorial.

SOURCE: Cedars-Sinai Medical Center, news release, July 16, 2008